Solar panels are being intensively studied in recent years since they are able to generate clean renewable energy by photovoltaic effect without causing an increase of atmospheric carbon dioxide or other dangerous gases in the atmosphere.
The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications.
A variety of solar panels for commercial and home appliances have been proposed.
A solar panel is typically made up of a set of solar photovoltaic modules electrically connected and mounted on a supporting structure. A photovoltaic module is a packaged interconnected assembly of solar cells.
The solar cell typically includes a substrate that can be for example made of metal or glass, a semiconductor active layer disposed on said substrate, and a transparent and/or conductive layer disposed on said semiconductor active layer.
Industrial solar cells typically comprise a semiconductor active layer made from monocrystalline silicon, polycrystalline silicon, amorphous silicon, CuInSe2, CuInS2, GaAs, CdS/Cu2S, CdS/CdTe, CdS/InP, and CdTe/Cu2Te-based multijunction material systems.
More recently other technologies are emerging in the field of photovoltaic applications, among which mention can be made of organic photovoltaics, dye-sensitized solar cells (DSSCs) and quantum dots solar cells.
In particular, dye-sensitized solar cells (DSSCs) are currently attracting great interest owing to their low production costs and high energy conversion efficiencies to be a potential alternative to conventional photovoltaic devices.
The use of fluoropolymer materials in compositions suitable for use in solar cells is already known in the art.
In particular, it is already known to use films comprising a top coat layer made of an optically transparent fluoropolymer as protective films suitable for use in solar cell modules.
A protective film is needed in a solar cell module to protect it from heat, humidity and from any possible environmental exposure or risk during transport. The protective film is typically optically transparent in order to allow the solar light to reach the solar cell module active layer.
However, fluoropolymer films known in the art have the drawback that mechanical stress on the film surface generates a haze effect that leads to a loss of the film transparency so that the operation of the solar cell is compromised. Since a solar cell module is normally exposed to a natural environment for a long time, it is mandatory that the material forming the protective film thereof has excellent hardness, abrasion resistance and impact strength so that it can protect the solar cell from any possible event (rain, hail, wind, sand, etc).
Moreover, some of the fluoropolymer protective films known in the art require either the use of adhesives or particular treatments in order to ensure their bonding to the solar cell.
Also, in several electrochemical devices such as DSSCs, optical shutters, secondary batteries and super capacitors, the presence of a liquid electrolyte triggers several problems including the leakage and evaporation of the liquid solvent, the possible desorption of the attached dyes and the corrosion of the counter electrodes, which limit the long-term performance and practical use of these devices.
Several methods have been proposed to reduce the evaporation and leakage of the liquid electrolyte by using solid or gel materials in substitution for the liquid electrolyte. The main alternatives include gel materials incorporating redox couples. However, the ion diffusion and conductivity characteristics of the solid and gel electrolytes are usually less than that of a liquid electrolyte.